At the present time, existing technology utilizes equipment and instrumentation in the hospital setting and industrial clean-room environment requiring sterilization. Current cleaning methods, however, are not acceptable for decontaminating the various devices that have been implemented in these settings. In particular, data collection devices have become important in tracking vital signs of a patient and their location within the hospital. One such device includes the portable data terminal (PDT) used to communicate real-time information between patient and medical professional. For example, as medical professionals frequently monitor a number of patients in telemetry or triage, the PDT interfaces with multiple users and is exposed to multiple settings where blood, body fluids, dust, debris and pathogenic organisms can contaminate the surface. As PDTs and other electronic instruments become more utilized throughout a clean medical environment, sterilization of the devices becomes essential to sustaining their use in these facilities.
Current cleaning methods such as using warm water and mild detergents to minimize any damage to the housing or user interface of the device do not adequately sterilize the equipment. Thus, microorganisms may be shielded within air bubbles or under dirt, grease, oil, or clumps of microorganisms. Furthermore, cellular proteins and other byproducts may reduce the efficacy of some liquid germicides.
Similarly, any subsequent chemical treatments to clean the device may cause damage to both internal and external components of the device, potentially interfering with the necessary communications between a patient and the medical professional. Typically, disinfecting solvents such as benzenes and alcohols (with a low residue), chlorination and alternative disinfectants are used to clean a PDT following the pre-washing step. These chemicals have been known to disintegrate the plastic composition of the housing and user interface of a PDT. This further creates the potential for damage to the optical electronics that are indirectly exposed to such treatments through crevices in the manufactured PDT. Unfortunately, the chemicals that may disinfect may not necessarily sterilize the device from contamination by microorganisms and pathogens.
Although hospitals use chemicals and high temperature steam (i.e. autoclaving) for sterilizing surgical instruments, these methods are inappropriate for use with an electronic device or electronic instrumentation. Chemical and steam sterilization are not even practical for the widespread sterilization for common devices. Moist or dry heat and chemical sterilants do not produce desirable levels of sterilization as necessitated by sterile and surgical needs of the medical profession. These current attempts undoubtedly cause damage to the PDT. Alternatively, gamma radiation may be used, as applicable for single-use medical supplies that do not tolerate heat and pressure or chemical treatments, but creates safety hazards for the user. Thus, present measures for sterilizing medical electronic devices have not been successful in providing necessary sterilization without delivering undesirable effects from thermal, chemical or ionizing radiation treatments.
To achieve desirable sterilization results, researchers have looked toward the effects of ultraviolet (UV) radiation. Although the light emitted from UV lamps has proven to be germicidal at about 260 nm wavelengths, and can be used to reduce the number of pathogenic microorganisms on exposed surfaces and in air at about 280 nm wavelengths of the electromagnetic spectrum, the UV lamp light has poor penetrating power. Accumulations of dust, dirt, grease, or clumps of microorganisms shield microorganisms from direct exposure required for the UV lamp light to be lethal. In addition, lamp age and poor maintenance of the UV lamp reduces performance. Furthermore, because UV lamps are typically larger, relative to the size of the object being sterilized, it may be more difficult to develop illumination configurations that do not cause shadows or regions of reduced radiation on the surfaces of multisided objects.
Conventional UV lamps have included low pressure and medium pressure monochromatic and polychromatic mercury vapor arc UV lamps, but do not deliver magnitudes of irradiation as required for inactivation of nucleic acid repair and replication mechanisms, and thus requiring long exposure times. Low pressure lamps, inherently low power devices with a very limited range of disinfection, are not capable of complete microbial decontamination. In addition, these lamps have high output variability. Medium pressure lamps produce a wider UV spectrum and generate levels for sterilization, but are very limited due to their high operating temperatures (400-1000° C.), non-uniform behavior, low electrical efficiency and high cost. (“Disinfection by Ultraviolet Radiation.”Disinfection, Sterilization, and Preservation. Blatchley, Ernest R. III and Peel, Margaret M., Ed. Seymour S. Block, Philadelphia: Lippincott Williams & Wilkins, Fifth Edition, 2001, p. 828). Luminous efficiency of these lamps is no greater than about 5%, leaving about 95% of the energy lost as heat. Id. The toxicity of mercury also presents a safety concern.
Further advances in engineering mercury vapor arc lamps have led to peak power pulsed UV light (i.e., the Pulsed Xenon Arc Lamp by Xenon Corporation). However, only 45-50% of the input energy is converted to optical energy when operated at optimum conditions. See Xenon Corporation, Chapter 5, SteriPulse Products, p. 19. Collection and redirection of the UV energy is critical to achieving the necessary sterilization effectiveness. Although the pulsed UV light may provide greater sterilization than conventional measures, the system may easily succumb to design errors. Improper or inefficient optical design dissipates heat and reduces optimization of its energy use.
Current needs for decontamination exist in environments requiring sterility. Such needs are present in various industries including: medicine and surgery, food decontamination, medical device and pharmaceutical packaging, sterilization in industrial clean rooms, inactivated vaccine manufacture, air disinfection and water decontamination systems. Although cleaning a data collection device with solvents may potentially remove extraneous substances from the device, this disinfection procedure does not efficiently sterilize the device for use in the sterile setting. Despite various attempts, no biological material may be destroyed at all. Minute crevices and hidden/unexposed surfaces areas in the design of portable data devices limit manual attempts to sufficiently decontaminate the entire device from bacteria, fungi, and various pathogens.
Significant developments have been achieved in the emerging technology of highly efficient light emitting diodes (LEDs). With luminous efficiency at least two times better than incandescent lamps, LEDs are much longer lasting light sources than incandescent lamps. One limitation in developing this technology, however, has been the availability of LEDs in a multitude of spectral ranges/colors. Currently, LEDs in the medical setting have been used in the therapeutic medical treatment of patients including removal of acne and wrinkles, (blue and yellow LEDs) and for the reduction of muscle pain or increased collagen content in the body (red LEDs). Only recently were UVLEDs demonstrated. Limitations still exist, however, in implementing LEDs as broad-band sources of illumination from UV to far-infrared radiation. These limitations include the effects of the LEDs' energy efficiency and the difficulty in configuring systems that could potentially damage internal electrical or optical components. Furthermore, direct illumination causes shadows or regions of reduced radiation on the surfaces of three-dimensional objects.
With increasing demands for the sterilization of instrumentation and electronic devices for use in sterile or clean-room environments, there is a need for a system that will efficiently decontaminate and sterilize the surfaces of the devices. Such a system or apparatus will be capable of inactivating any residual microorganisms on the surfaces of a PDT for complete biological decontamination. The sterile apparatus will provide a system for sterilizing hard to clean data devices to effectively eliminate the transfer of pathogenic organisms between patients and minimize the spread of germs and disease. In addition, the apparatus will be capable of being sterilized without causing damage to internal or external components of the device. Accordingly, sterilization of the data device in between shifts of employees, such as changeover of nursing or medical staff, or in between interactions with patients will be beneficial to maintaining the sterility of the hospital setting. The apparatus should therefore be resilient to repeated sterilization effects and remain fully functional before and after sterilization.
Furthermore, a system designed for high throughput applications in the hospital setting would greatly benefit both patients' and medical professionals' safety concerns. The development of energy resources will also contribute to the design of a system for use in sterilizing medical instrumentation and electronic data devices.